This research clearly shows higher spoilage rates by minorities. It also shows minorities did not use most of their ranks, which lead to higher number of ballots tossed out of the vote count.

It points out some strange results with RCV such as "Raising a candidate's rank on one's ballot does not always increase that candidate's chance of winning and in fact may decrease a candidate's chance to win" (p.21) - which means your vote can hurt your candidate rather than help them. This phenomenon is unique to the RCV style voting.

At over 80 pages, it is extremely thorough and worth the effort to read.